Selectable dual mode triggers for semiautomatic firearms are known, which include triggers capable of actuating and firing rounds on both pull and release of the trigger. Examples of such systems are disclosed in U.S. Pat. No. 8,667,881 B1 to Hawbaker, granted 2014-03-11 (herein “the '881 Patent”), and U.S. Pat. No. 8,820,211 B1 to Hawbaker, granted 2014-09-02 (herein “the '211 Patent”) (collectively “the Hawbaker patents”), both of which are incorporated herein by reference. The characteristics of selecting modes of actuation in which only one round is discharged with one function of the trigger was approved by the ATF and granted the patents mentioned above and incorporated herein.
The introduction of a trigger that actuates on both pull and release presents several challenges. For example, during the testing of this new trigger, misfires were sometimes experienced due to light primer strikes, unexpected trigger states during actuation, and magazine changes. It quickly became apparent that improvements were needed to address these and related issues. In working to solve these problems, innovations were discovered that have applicability to not only pull-and-release triggers, but also to semiautomatic firearms generally.